The invention relates to a protective hood for wood-milling machines.
A protective hood of this nature forms the subject matter of EP-B 558 692. It is for machining curved workpieces, and utilizes a guide element which may be a curve-milling stop or an approach ring in combination with an approach strip. If straight workpieces are to be machined on the stop, for example with the aid of stop plates, which can be adjusted with respect to one another, of an xe2x80x9cintegral stopxe2x80x9d as described in EP-B 215 040, it is necessary to remove the protective hood for the curve milling and to fit a protective hood on which the stop plates can be arranged on the machine table. This change-over work is not only time-consuming, but, due to the considerable weight of the devices which have to be moved, generally also requires two people or appropriate lifting and cutting units.
An object of the present invention is to provide a protective hood for wood-milling machines which is designed in such a way that it can remain on the machine table as a universal basic element and can be used both for the installation of stop plates and for curve-milling work.
In a protective hood of the generic type the preamble of patent this object is obtained by a holding member for the movable attachment of a stop plate arranged on each of the two side walls of the protective hood, which holding member is formed of a side limb, releaseably attached to the side wall, and a front limb, which is at right angles to the side limb and bears the stop plate. The term covers not only the preferred option of removing the holding members altogether when required, but also the alternative of, for example, pivoting these members backward or sliding them upward, in order to provide sufficient space in the lower region of the protective hood to mill annular or curved workpieces. To be able to change from milling on the stop to curve milling, it is in any event sufficient to release the two holding members bearing the stop plates in accordance with the invention, so that the curved machining of wooden workpieces is possible without restrictions.
In this context, it is advantageous if the side limb is horizontally adjustable relative to the side wall of the protective hood, the two side walls of which engage in a horizontally displaceable manner in two parallel guide rails which are attached to the machine table. In this way, each of the two side walls of the protective hood can be adjustably attached to the guide rail by means of a clamping member.
According to the invention, it is possible to adjust either the entire unit, protective hood and stop plates, forward or backward via an adjustment mechanism or to adjust only one of the two stop plates on the protective hood relative to the other stop plate. The adjustment mechanism may be provided either on the protective hood or on the holding member.
The adjustment mechanisms may have adjustment spindles which can be actuated manually, and may be arranged in box-like housings which form the side limbs of the two holding members. In one of the two holding members, the adjustment mechanism is designed in such a way that it is used for the horizontal displacement of the entire unit, comprising the basic device (protective hood) and the two fitted stop plates, while the adjustment device in the other holding member is provided for relative displacement between the latter and the protective hood.
In an alternative embodiment, the two adjustment mechanisms are accommodated in the hollow side walls of the protective hood and are driven synchronously by two electric motors which displace the protective hood and any fitted stop plates together in the horizontal direction. By synchronously activating the two electric motors, it is possible to bring about easy, non-jamming movement of the protective hood, with the additional possibility of inputting the desired parameters via a keyboard using suitable control programs. In this solution, the relative displacement between one of the two stop plates and the protective hood is preferably carried out by a further electric motor which is accommodated in the side limb of the corresponding holding member.
In a refinement of this embodiment, it is particularly advantageous, in order to clamp the protective hood securely on the guide rails, to provide, in both side walls, a motor which drives a vertical spindle which acts as a clamping member. In this way, it is possible to input the desired parameters at the keyboard, so that not only the adjustment of the protective hood and the stop plate, but also the fixing of the protective hood in the working position reached, are carried out automatically.
According to another feature of the invention, the cover comprises a fixed support surface which is connected to the rear wall and on which a preferably transparent cover flap is articulatedly mounted via a hinge, which flap bears a pull-out extension plate with a rim which projects downward and on the front side of which the protective shield is arranged in a vertically adjustable manner. In this way, by pivoting up the cover flap, unimpeded access to the interior of the protective hood is created, in order, for example, to exchange the milling tool.
According to a further feature of the invention, the support surface has means for attaching a bearing block for the pivot arm of a protection and pressure device, for example in accordance with EP-B 637 276.
The various features of novelty which characterize the invention are pointed out with particularity in the claims appended to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects obtained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.